Similarities Between Chimpanzees and Human Beings

Chimpanzees and humans differ by just over one percent of DNA, and there are striking similarities in the composition of the blood and the immune responses. In fact, biologically, chimpanzees are more closely related to humans than they are to gorillas. Some have proposed including chimpanzees in the same genus as human beings to recognize these similarities, calling them Homo troglodytes.

Intelligence
The anatomy of the chimpanzee brain and central nervous system is startlingly similar to our own. It should not be surprising, then, that the chimpanzee (along with gorilla and bonobo) is capable of intellectual performances once thought unique to humans. In the wild, chimps must constantly make decisions, such as which group they should join, whether to be peaceful or aggressive, for example. They are capable of sophisticated cooperation in hunting. They use more tools for more purposes than any other creatures except ourselves. And they show the beginning of tool-making behavior.

Communication
In captivity chimpanzees can be taught human languages such as ASL (American Sign Language), learning 300 or more signs. They can master many complex skills on computers. It has been demonstrated that chimpanzees are capable of reasoned thought, abstraction, generalization, symbolic representation and a concept of self. Although it is difficult to quantify emotions, those who have worked closely with chimpanzees agree that they feel and express emotions such as sadness and happiness, fear and despair - and they know mental as well as physical pain. There are uncanny similarities in the nonverbal communication patterns of chimps and humans - kissing, embracing, patting on the back, touching hands, tickling, swaggering, shaking the first, brandishing sticks, hurling rocks. And these patterns appear in similar contexts as those in which they are seen in humans. They mean much the same.

Childhood
Chimps, like people, have a long childhood - five years of suckling and sleeping in their mothers' nests at night. After the birth of a new baby, an older child remains emotionally dependent on its mother and continues to travel with her for the next three to four years. Bonds formed between mother and offspring and between siblings during this intense association period are likely to persist throughout life. This long childhood is as important for the chimp as for the human child. A young chimp has much to learn. And because of the chimp's fascination with the behavior of others and ability to imitate and practice observed actions, certain patterns are passed from one generation to the next. When a mother dies her orphaned offspring may be unable to survive. He or she shows signs of clinical depression, and feeding and play activities decline. Older siblings, including males, often adopt their orphaned brothers or sisters. Occasionally individuals adopt infants not related to them - instances of true altruism.

Biological Make-Up
Chimpanzees are so like us biologically that they can catch or be infected with all known human infectious diseases (with the possible exception of cholera). This is why they are used in medical research. Gradually, researchers are beginning to admit that the similarities in behavior, intellectual performance and emotions are equally striking. This is leading to improvements in the conditions in some medical research labs. Ultimately we hope it will no longer be considered ethical to use them at all.

Significant Differences
Jane Goodall's study of chimpanzees not only points to striking chimp-human similarities but also pinpoints differences. Perhaps the most significant of these is the fact that chimpanzees have not developed sophisticated spoken language. Humans can teach their infants about things or events not present, share knowledge of the distant past, make plans for the distant future, discuss an idea so that it grows as a result of the accumulated wisdom of the group. The fact that chimpanzees can learn from humans, to communicate using human languages such as ASL (American Sign Language used by the deaf) or computer or other lexigrams, does not minimize this difference. It is our language that has enabled our species to become so dependent on culturally transmitted behavior. Our intellect dwarfs that of even the most gifted chimpanzee. There are, of course, very many physical differences as well. One is in the structure of the vocal tract, as mentioned. Chimpanzees have not developed the upright posture of humans. The anatomy of hands and feet is very different. Female chimpanzees and bonobos (but not female gorillas or orangutans) show sexual swellings during periods of estrus.